system hardware

[giphahne]

Bill of Materials for Physical Device:

• 2 x Raspberry Pi 3
  • Due to the way the RFID scanner and relay(s) are hooked up, it would probably be more cost effective to hold off on two RPi3s for now, and just get an extra SD card or two. (of course, on the other hand, there are worse things than having an extra Pi or two around...)
• 1 x 2 channel relay module
• 1 x RC522 RFID Reader
• 1 x 5V power supply (DIN rail)
  • strictly speaking, it would be desirable for the relay(s) themselves to be isolated from the RPi (so the 5V power for the relay coils isn't being supplied through the RPi, only the HI/LOW state of the Opto-isolated control pins is physically connected to the RPi). The simplest way I know of to do this is to power the relay board with an additional/separate 5V supply. (but perhaps someone else has better ideas?)
• 1 x Cord end
• 1 x assortted cable bulkhead fittings
• 1 x assorted jumper wires
• 1 x LED
• 1 x momentary pushbutton 22mm
• 1 x Enclosure for RFID reader and button
• 1 x Enclosure for Controllers / relay
• 1 x Mounting plate for controllers / relay
• 1 x DIN rail
• 20 x misc DIN connectors
• 40 feet irrigation cable 18 ga x 10 conductor - home depot

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Bill of Materials with links:

• 2 x Raspberry Pi 3
• 1 x 2 channel relay module
  • this board is opto-isolated and requires 20 ma
  • amazon
• 1 x RC522 RFID Reader
  • amazon
• 1 x 5V power supply (DIN rail)
  • mouser
• 1 x Cord end
  • amazon
• 1 x assortted cable bulkhead fittings
  • amazon
• 1 x assorted jumper wires
• 1 x LED
• 1 x momentary pushbutton 22mm
  • automationdirect
• 1 x Enclosure for RFID reader and button
  • polycase
• 1 x Enclosure for Controllers / relay
  • polycase
• 1 x Mounting plate for controllers / relay
  • polycase
• 1 x DIN rail
  • polycase
• 20 x misc DIN connectors
• 40 feet irrigation cable 18 ga x 10 conductor - home depot

[agriboss]

Sounds good on the single PI... we can always add the second if needed in the future

Re: the 5V power, the pi and relay module would be wired in parallel (a wire for each coming from 5V power supply). The relay module has an optocoupler on each channel so the GPIO would just be driving the optocoupler, with the relay coil being driven from the 5V supply